Variable-pitch blade control ring axial warping prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbine engine variable-pitch vane control rings experience axial warping during operation, leading to angular pitch errors and incorrect vane positioning, which affects aerodynamic performance, particularly in mono-actuator systems and when using casings with high expansion rates.
Innovation Solution
The introduction of axial and/or helical guiding means, including radial fingers and grooves, that cooperate by axial abutment and sliding to limit or prevent axial warping, ensuring accurate vane positioning and aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a control ring with radial openings and pins is used to connect levers to vanes, then the vanes can be actuated to rotate about their axes, but axial warping of the ring occurs during operation causing angular pitch errors
Solution Approach 1:
The invention adds axial guidance constraints in the axial dimension to control the ring's movement. By introducing fingers that slide in axial grooves and abut against the casing, the ring's axial position is controlled, preventing warping while maintaining rotational actuation capability.
Solution Approach 2:
The fingers act as intermediary elements between the control ring and the casing. These fingers transmit axial constraints from the casing to the ring, preventing the ring from warping axially while allowing it to rotate for vane actuation.
2Temperature
If aluminium material is used for the ring body, then thermal expansion differences compensate for high casing expansion rates, but the warping phenomenon is accentuated
Solution Approach 1:
The invention controls the ring's shape stability by adding axial constraints through fingers sliding in grooves. This axial guidance prevents the ring from warping out of plane, maintaining shape stability even when aluminium material is used for thermal expansion compensation.
3Device complexity
If a single actuator is used to rotate the control ring, then the device complexity is reduced, but significant deformation occurs in the zone diametrically opposite the actuator connection
Solution Approach 1:
The fingers serve as intermediary elements that distribute the mechanical constraints around the ring. By sliding these fingers in axial grooves and abutting against the casing, the ring's shape is maintained even in the zone diametrically opposite the actuator, preventing significant deformation while keeping the actuation system simple.
4Adaptability or versatility
If the control ring is rotated about the turbine engine axis, then the angular pitch of stator vanes is adapted to operating points, but axial warping causes incorrect positioning of the vanes
Solution Approach 1:
The invention adds axial guidance constraints to control the ring's movement in the axial dimension. By introducing fingers that slide in axial grooves and abut against the casing, the ring maintains its planar shape during rotation, ensuring accurate vane positioning while preserving pitch adaptation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents axial warping, maintaining precise vane positioning and enhancing the aerodynamic performance of the turbine engine by stabilizing the control ring against thermal expansion and actuation-induced deformations.
Implementation Method 1
first means for guiding in an axial and/or helical direction along said axis, which first means are supported by a first one of the elements selected from said body and said casing and comprise at least one finger that is substantially radial relative to said axis and that comprises axial abutment means configured to cooperate by (axial) abutment with at least one first surface of a second one of said elements and by sliding with said surface
Data Source
AI summary
Variable-pitch blade control ring (44) for a turbine engine, including an annular body (42) configured to be mounted so as to be rotatable about an annular casing (16) of the turbine engine. The body links to levers (34) for connecting to the vanes. The ring has a mechanism for guiding in an axial and/or helical direction, supported by the body. The mechanism includes at least one substantially radial finger (60, 62) for axial abutment on at least one first surface (72, 74) of the casing and for sliding on the surface.